Really the suggested size for even a tiny dwarf O. Mercatoris is 30 gallons, but if you are familiar with keeping saltwater tanks and are diligent about water changes, tank maintenance, and all that you could probably keep a Mercatoris in your 18 gallon. Honestly they aren't very interactive, and they only come out late at night after the lights have been out for a while. My first octopus was a Mercatoris, and even though he was a juvenile when I bought him, he only lived for 4 months.

For now, you should read the ceph care articles on this website. They will answer most of your questions, and probably clarify any other things you didn't think of yet. Just click on the "ARTICLES" link underneath the large TONMO logo at the top of the webpage.

Unfortunately, 18 gallons is a bit smaller than what we recommend even for the dwarf octos, since cephs produce so much waste... it might be OK for a juvenile, but even a dwarf would be likely to outgrow it. Occasionally folks come here saying they already have an octo in a small tank, and they don't always die, but a lot of them do, so I think the safest choice would be to set up a larger tank if you're interested in an octo. Most of the species that are interactive and outgoing are a bit larger, so although dwarf species are appealing for size, they tend to be short-lived, shy, and nocturnal, so considering a larger octo like a bimac is highly recommended.

yeah, been readin them. would there be any small interactive ones that could bein an 18 gallon? thats one of the reasons that i want to get one, is that they sound liek interactive playful little critters. but to start out a less interactive one would do if nothing else could go in it.

and i will definatly try to do what you said to keep water good.

would a small one be able to live or go through hamster tubes? i read tubes are good for them to have for different things and my sister still has her hampster cage in the garage after hers died, lots of tubes i could use. (i would clean them of course)

None of the octo's you could fit in an 18 gallon will be "playful" or interactive. I would suggest not using the hamster tubes if they were previously used, whether you clean them or not. Hazardous things can leach out of the plastic into the water. You have the right idea though.

You should really consider finding a 50 gallon or larger tank, and a larger species octopus. Keep in mind, you don't only need a tank to keep it in, but lots of live rock, a good protein skimmer, and an over-sized filter like a wet/dry or sump/refugium, and possibly even a chiller depending on what area the octopus comes from. It is expensive to set up a proper habitat for a ceph of any kind, and then on top of all that, you might have to supply it with live food for the duration of its life, which is quite expensive also.

i'm 14 so i don't really have a large bugdet to come from and it will take a few weeks just to get the money for the octo himself. what would be an ok size thats not too awful big?

and if i did oftne water changes and kept the water quality good, would it still just be a little small for a dwarf?

thanks for the help guys.

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It's not impossible to keep one in a tank that size, but the smaller the tank is, the faster your water quality will diminish, and the harder it will be on the octopus. It's really not a good idea to start with that small of a tank. Not only is water quality harder to keep, but just overall water parameters will shift greatly very quickly, and it's very stressful on the animal.

Not trying to be a killjoy, but understand that keeping an octopus is not easy at all, and it's not worth risking. It would be really disappointing to get one and it dies because you didn't spend the extra money getting a good setup for it. Make sure you can provide it with the best possible home before you get one.

Patience is the hardest thing when it comes to this kind of situation, but it will pay off greatly in the long run. Take your time, buy the things you need over the next several months, and it will be more rewarding, and you will be more likely to get the experience you were hoping for!

and is a protien skimmer nessacary to start out with? cuase i always add on to my tanks after a while. what would be the nessesaties to stat with?

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Yes, absolutely. Protein Skimmers are argueably the BEST filtration you can have on a saltwater system. They imitate the oceans natural method of removing junk from the water. Plus, they will suck out any ink if the octopus gets startled, which is not uncommon.

gonna check prices on custom building one, unelss that is a dangerous idea?

my birthdway and crhistmas, both in december, will be mainly asking for seahorse supplies, i'll be getting a 50 gallon or so tall tank for them and have to get stuff, wich i would prefer my relations to get me, haha. so i'll just save up what i can for the octo over the next several months like you said. what do you think would be the total price of a starter setup? just thigns needed to begin with. so i can get an idea

That's hard to determine. I wouldn't try building a skimmer to start with. That's a pretty advanced experiment, and it wouldn't be cool to spend the money on the materials and end up with a piece of junk. Where do you live? Maybe there is a local marine aquarium society? If you live in or near a large city there probably is, and if so, you can usually buy used equipment from members for pretty cheap. Plus, they could help you figure out how to set it up, and how to maintain your water.

A good protein skimmer might run you anywhere from $100 up to $300, even more for some of the real fancy skimmer/sump combos. As far as a tank goes, you should try to find one that's pre-drilled... or set up for a sump. This will let you put all of the extra equipment in the sump, and not in the display tank. One of the pains of having a regular aquarium, is that you have to seal all of your equipment so it doesn't get sucked in or escape through cracks between your equipment and lids. With a sump, you only have to worry about the intake being screened off, which is pretty easy. Then again, you have to plumb the sump to the tank, buy a good pump to return water back to the tank from the sump.... oh man. Yeah, you need to do lots of reading!

As an example though, I bought a pre-drilled 72 gallon bowfront tank, with stand, canopy, lids, and completely ready sump with all the plumbing, and with a protein skimmer, for $500 cash from a local aquarium society member. It's everything I would need for an octopus, minus lighting, and lighting is really cheap considering you don't need anything fancy, just low-wattage fluorescents.

yep, been studying and reading about seahorse keeping, caring, breeding, etc for about 6 months now. gonna get a 50 gallon lots of rock and stuff for christmas and birthday, and let it sit there for about 5-6 months to let it get good, buy a couple females to start out with then when i think i'mr eady get a male or a few.

anyway, i ment build a tank. i wouldn't know where to start with a skimmer

i hope all this work and money will be worth it! but it sounds like to me it will

yep, been studying and reading about seahorse keeping, caring, breeding, etc for about 6 months now. gonna get a 50 gallon lots of rock and stuff for christmas and birthday, and let it sit there for about 5-6 months to let it get good, buy a couple females to start out with then when i think i'mr eady get a male or a few.

anyway, i ment build a tank. i wouldn't know where to start with a skimmer

i hope all this work and money will be worth it! but it sounds like to me it will

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Okay, well sounds like you've got the right attitude. You'll definitely figure out a lot with the experience you'll get out of keeping the seahorses.